gas chromatography

This term refers to a specialized analytical chemistry technique. It is used primarily in forensic science, environmental monitoring, and pharmaceutical quality control to determine the purity of a substance or the specific components of a complex mixture.

As a technical term for a specific scientific process, it is an uncountable noun. It describes the method itself rather than a discrete object, meaning it does not have a plural form and is not used with indefinite articles like "a" or "an" unless followed by a countable noun such as "system" or "method."